Search results for "Electrodialysi"

Fluid-structure interaction in electromembrane processes: modelling of membrane deformation, fluid dynamics and mass transfer

2018

In recent years, water and energy supply issues have boosted a noticeable interest in the scientific community on electromembrane processes such as electrodialysis and reverse electrodialysis. In order to gain an important place in the industrial market, technological challenges on various aspects are involved for the optimization of these processes. In this context, profiled membranes exhibit interesting performances and offer countless geometric alternatives. However, the mechanical behavior of the membranes and its interaction with fluid dynamics has been poorly investigated so far. In membrane-based processes, a trans-membrane pressure (Ptm) between the different solutions flowing throu…

The REAPower Project: Power Production From Saline Waters and Concentrated Brines

2019

Aim of this chapter is that of describing in detail the REAPower project from the very beginning up to the testing of the pilot plant built at the end of the project.

Multi-physical modelling of Reverse ElectroDialysis

2016

Energy extraction from salinity gradients (salinity gradient power, SGP) represents a novel and valuable renewable energy source. Among the existing SGP technologies, reverse electrodialysis (RED) is the oldest and one of the most promising. RED is a membrane-based electrochemical process that directly converts the salinity gradient energy into electric current. More precisely, in a RED unit two solutions at different concentration flow in two series of alternated channels, which are formed by piling two alternated series of cation and anion exchange membranes (CEMs and AEMs, respectively). The chemical potential difference between the two solutions generates an electric potential differenc…

A multi-physics modelling tool for Reverse Electrodialysis

2015

In this work, a multi-physics modelling approach has been developed for the RED process.

Computational Fluid Dynamics of Reverse Electrodialysis Systems

REVERSE ELECTRODIALYSIS HEAT ENGINE: Low-grade Waste Heat into Electricity

Our society is undergoing a progressive change about the life style and habits. The world population is continuously increasing with 7.6 billion of human beings in 2018, resulting in an increasingly demand of resources in terms of food, water and energy. The exploitation of the planet resources since the first Industrial Revolution, results today in an unsustainable condition, which requires fundamental changes. In particular, in the energy sector the adoption of fossil fuels as the main energy source for human beings’ activities resulted in a strong impact on our planet, leading to climate changes and environmental pollution. Nowadays these aspects have induced society to a substantial cha…

Modelling Reverse Electrodialysis process via Exergy Analysis

2017

Salinity Gradient Power Heat Engines (SGP-HEs) represent a novel technology to convert low grade waste heat into electricity. Reverse Electrodialysis Heat Engine (REDHE) is one of the possible application of this concept, where a common RED unit is coupled with a thermal regeneration unit supplied with waste heat to restore the salinity gradient of the streams to be fed back to the RED unit. In a RED unit, anion and cation exchange membranes (AEMs and CEMs) are alternatively stacked and interposed between salt solutions at different concentration generating an electric potential difference over each membrane along with a selective transport of cations and anions from the concentrated soluti…

Exergy Analysis of Reverse Electrodialysis Heat Engine with Multi-Effect Distillation Regeneration Stage

2018

The increasing worldwide energy demand is rising the interest on alternative power production technologies based on renewable and emission-free energy sources. In this regard, the closed-loop reverse electrodialysis heat engine (RED-HE) is one of the most promising technologies currently under investigation. This technology produces electric power by harvesting the salinity gradient energy released from the controlled mixing of two artificial salt solutions with different concentrations. Low-grade heat (T < 100 °C), derived from any industrial process is used in a multi-effect distillation (MED) unit to restore the initial salinity gradient of the solutions. In this work, a comprehensive…

CFD simulation of Electrodialysis channels equipped with profiled membranes

Electrodialysis (ED) is a membrane-based electrochemical process that remove ions from a solution. The main use of ED is for the production of drinking water by brackish water desalination, but there are several other applications. ED is characterized by the coexistence and the interaction of different physical phenomena that affect the stack performance. Among them, fluid dynamics and mass transport are crucial: concentration polarization affects the limiting current density and the non-Ohmic voltage drop due to the chemical potential difference between the two solutions; pressure drop affects the pumping power consumption. Moreover, the total energy consumption depends also on the Ohmic v…

A comprehensive multi-scale process model of bipolar membrane electrodialysis (BMED) systems

Bipolar membrane electrodialysis (BMED) uses electrical energy to produce acidic and alkaline solutions by water dissociation. Its great versatility has increasingly gained the interest in chemical/biochemical industry and in environmental protection. Co-ion leakages through the membranes and shunt currents pose major issues leading to significant drops in current efficiency. This work focuses on the development of a novel model based on a multi-scale approach. Four different dimensional scales were fully integrated within a comprehensive simulating tool with distributed parameters. The lowest scale, which is represented by the channel, includes two sub-models. The CFD simulations sub-level…